Reciprocable means for automatically moving a series of articles in tandem through a drying chamber



June 3, 1947. v. c. ENsoR ETAL 7 2,421,690

RECIPROCABLE MEANS FOR AUTOMATICALLY MOVING A SERIES OF ARTICLES INTANDEM THROUGH A DRYING CHAMBER Filed Sept. 8, 1944 3 Sheets-Sheet 1FIG.

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RECIPROCABLE MEANS FOR AUTOMATICALLY MOVING A SERIES OF ARTICLES INTANDEM THROUGH A DRYING CHAMBER Filed Sept. 8, 1944 3 Sheets-Sheet 2 E0. J0 NS TON June 3, 1947- v. c. ENSOR ETAL 2,421,690

RECIPROCABLE MEANS FOR AUTOMATICALLY MOVING A ssnms 0? ARTICLES INTANDEM THROUGH A mums cnmssn Filed Sept. 8, 1944 3 Sheets-She et 3477ORMSV which has an entrance door ll Patented June 3, 1947RECIPROCABLE MEANS FOR CALLY MOVING A SERIES OF AUTOMATI- ARTICLES INTANDEM THROUGH A DRYING CHAMBER Vernon C. Ensor, Woodlawn,

Johnston, Towson, Electric 1 Company,

and Fred D.

Md., 'assignors to Western Incorporated,

New York.

N. Y., a corporation of New York Application September 8, 1944, SerialNo. 558,186 7 Claims. (Cl. 34-53) This invention relates to dryingapparatus and more particularly to drying apparatus in which articlesare subjected to a drying cycle of at least a predetermined length.

In the manufacturing of some types of insulated cables it is necessaryto thoroughly dry the core portions of the cables before insulation isapplied thereon. Such portions must be dried for a minimum period oftime in order to make certain that the desired degree of dryness isobtained. In apparatus heretofore known for drying core portions it isdifllcult for operators to ascertain when the core portions have beendried the required period of time and to prevent the core portions beingdried from being removed from the apparatus before the expiration of therequired minimum period of drying.

An object of the invention is to provide new and improved dryingapparatus.

An apparatus constituting one embodiment of the invention includes anelongated oven having an entrance at oneend and an exit at the otherend. There are provided means for ,carrying a plurality of articles intandem through the oven and means for actuating the carrying means topresent an article at the exit of the oven at a predetermined period oftime after the next previous article has been presented at the exit.

A complete understanding of the invention may be obtained from thefollowing detailed description of a specific embodiment thereof, whenread in conjunction with the appended drawings, in which:

Fig. 1 is a fragmentary, top plan view of an apparatus embodying theinvention;

Fig. 2 is a fragmentary, front view of the apparatus;

Fig. 3 is an enlarged, fragmentary, sectional view of the apparatustaken 3-3 of Fig. 1;

Fig. 4 is an enlarged, fragmentary, sectional view of the apparatustaken 4-4 of Fig. 2;

Fig. 5 is an enlarged, fragmentary, vertical sectional view of a portionof the apparatus, and

Fig. 6is a diagrammatic view of an electrical circuit suitable for usein controlling the operation of the apparatus.

Referring more in detail to the drawings, there is illustrated thereinan apparatus for drying core portions of cables prior to the formationof insulating coverings thereover. This apparatus includes an elongatedoven I0 (Figs. 1 and 2), slidable along slidably supported vertical online vertical a rod l2 and an exit door IS on line a pair of hooks 24-24at one when closed. the oven l0.

upon arod H. The exit door I3, covers an exit opening is formed in Aramp I6 is provided in the oven identical with the ramp IS,

l1-l1 positioned in the oven III are supplied with steam from a suitablesource of steam (not shown), and serve to heat the interior of the ovenI 0. v

A pair of channel-like tracks 20 and 2| (Fig. 4) extend longitudinallyin the oven Ill. The tracks 20 and 2| serve to receive wheels 22-22rotatably mounted on dollies 23-23 (Fig. 2). The dollies are designed tocarry reels. 26-26 containing supplies of core portions which are to bedried. Each of the dollies is provided with end thereof, which connectthe dollies together in a train extending from the entrance end to theexit end of the oven, which train is in effect a conveyor. Each dollyalso has a pair of abutment plates 25-25 (Fig. 4) positioned near theforward end thereof.

. When a dolly 23 is in front of the exit door l3,

that is, in the position designated A in the drawings, it is accessibleto an operator of the apparatus and the operator can remove the dollyreadily. The dolly position next adjacent to position A to the leftthereof, as seen in Fig. 1, is designated position B and the dollyposition just to the left of positionB is designated position C. Thedollies in the oven l0, including that in position B and those extendingtherefrom to the entrance end of the oven, and the reels carried therebynormally are inaccessible to the operator and cannot be removed from theoven until they are moved successively to position A.

A carriage 30 (Fig. 3) provided with supporting rollers 3l-3l is mountedfor reciprocation along a trackway 32, which is positioned below thetracks 20 and 2|. The carriage 30 normally is located under a dolly 23in position B and may be moved'to a point below position A and back toits normal location. A pair of dogs 33-33 are counter-balanced on a pairof pins 34-34 secured adjacent to the end of the carriage 30 nearest tothe exit. The dogs 33-33 may be rotated in a clockwise direction, asviewed in Figs. 3 and 5, so that the upper ends thereof clear theabutment plates 25-25 of a dolly in position B and these plates arestruck by the dogs when the carriage 30 is moved to the left relative tothe dolly. However, when the upper ends of the dogs 33-33 clear theplates 25-25, the dogs are swung to vertical positions by the heavierlower portions Y posits to that in Fig. 3, the

Fig. 3.-

, opposite ends of dotted line position.

movement opens a rear secured to. the upper 3 thereof, which movement islimited by a bar 85. Thus, when the carriage 88 is moved to the right asviewed in Fig. 3, the upper ends of the dogs "-88 engage the abutm'ents25-25 of the dolly 28 in position B, and this dolly is moved to theright toward position A with the, carriage. Since the dollies areconnected, together by the hooks 24-24, all the dollies are moved tothe' right with the end dolly.

A pair of dogs 81-81 (Fig. 3), which are identical with the dogs mountednear the end of the carriage 88 opcarrying the dogs 81-81, and when isin its full line position, as shown lower portions of the dogs 81-81strike an abutment 88, which is secured to the oven in a positionbetween the tracks Thus, when the carriage is so positioned, the dogs81-81 are held against rotation by the abutment 88 andstrike theabutment plates 25-25 of the dolly in position C it an attempt is madeto move the dollies menu lly to the right as viewed in the carriage Aram 42 fastenedto a piston (not shown) .enclosed in a pneumatic cylinder48 is rigidly secured to the bar 85. A conventional four-way valve 44issupported on the cylinder 48 and is provided with a solenoid 45 and asolenoid 48,

which operate the valv 44,

of valve, and is connected by pipes 48 and H to the cylinder 48. Whenthe solenoid 45 is energized, the valve 44 is actuated to supply airinto the cylinder 48 so" as to cause the piston in the cylinder 48 todraw the rain to the right, as'viewed in Fig. 3, whereby the carriage 88is drawn along the track 82 from its full line position, as shown inFig. 8', to its This movement of the carriage 88 moves the dolly inposition Bfrom position B to position A.' When the solenoid 48 isenergized, the ram 42 is thrust to the left, as viewed in Fig. 3, andthe carriage 88 is moved from its dotted line position, as shown in thatfigure, to its full line position, the dogs 3. The dogs 88-88 thenprevent the train of dollies from being moved to the left, while thedogs 81-81 prevent the dollies from being moved to the right. I

. A rod 41 (Fig. 3) is secured to the bar 85 and rests in a U-shapedguide 48. When the carriage 88 is moved to its full line position, anarm carried by the rod 41 strikes a springressed arm 58 and moves thearm 58' from its position shown in dotted lines to that-shown in "fulllines, which limit switch I.

A curved arm 52 (Fig. 3) is rigidly mounted on a vertical rod 58, whichis rotatably mounted in a pair of bearings 54-54 secured to the wall ofthe oven I8, and a kicker 55 (Fig. 1) is rigidly end of the rod 58. Aspring- 58 of a forward limit switch 51 northe kicker 55 to its fullline position. as shown in. Fig. 1. In this position the arm 52 is inthe path of a dolly'in position A, and when a dolly is moved forwardfrom position B to position A by the carriage 88, it and moves it to itsdotted line position, whereby the kicker 55 moves the spring-pressed arm58 to-its dotted lineposition to actuate the forward limit switch 51.

The forward limit switch .51 (Figs. 1 and 6) includes a pair of contactsand N and a contactor 82. when the spring-pressed arm 58 is in dolly inposition pressed arm maily urges 88-88, are pivotally The four-wayvalve. 44 is a standard bleeder-valve-controlled type 88-88 and 81-81clearing the plates 25-25 of the strikes the arm 52' s by the'contactor28 and 2I.'

its full line position, as shown in Fig. 1, the contactor 82 is inengagement with the contact 88. When the spring-pressed arm 58 is movedto. its dotted line position, the contactor 82 is brought intoengagement with the contact 8|.

The contact 88 (Fig. 8) is connected by a conductor 88 to a contactor 84of a relay 85. when the relay is not energized, the contactor 84 is inengagement with a contact 88 of A conductor 18 serves to connect thecontact 88 to a contactor H of a normally open relay 12. The relay 12includes a contact 18. which is engaged 1I when the relay 12 isactuated. The contact 181s connected by a conductor 14 to a winding 15of the solenoid 45.

A conductor 18 (Fig. 6) connects the winding 15 to a conductor 11, whichis connected to a winding 88 of the solenoid 48-. A conductor 8Iconnects the winding 88 tom contact 82 of the relay 85. A contactor 88of the relay 85 is brought into engagement with the contact 82 when awinding 84 of the relay is energized. The contactor 88 is connected byconductor 81 to a conductor 88 of a power line 88., The conductors 88and 81 are connected by a conductor 88 to the con-- tactor 82. The powerline 88 includes a conductor 8i, which has a manually operable switch 82therein and is connected to a conductor 88.

The conductor 88 (Fig. 6) is connected to a conductor 84, to theconductor 11, and to one end of a filament 85 of an incandescent lamp88. The other end of the filament 85 is connected by a conductor I88 toa conductor IN. The conductor IN is connected to the contact 8| of thelimit switch 51 and to a normally closed contactor I82 of the limitswitch 5I. The con-' tactor I82 is normally in engagement with a con.-tact I88, which is connected by a conductor I84 to the winding 84 of therelay 85. The contactor I82 is connected by a conductor I85 to a contactI88 of the relay 85. A contactor II8 of the relay- 85 serves to engagethe contact I88 when the winding 84 is energized, and is connected by aconductor III to the conductor 81.

The conductor II2 of a conventional timer II8. A conductor .4 serves toconnect an end of a clutch coil II5 of the timer to the conductor 84,and a conductor II8 connects the other end of the clutch coil II5 to aconductor I28. which is connected to the motor N2 of the timer and tothe contactor 84.

The conductor I28 has therein a normally closed safety limit switch I2I,which is opened by the timer H8 in case of failure of the apparatus andthereby prevents damage to the apparatus.

The timer II8 (Fig. 6) includes a normally open main contact I22, whichis conductor I24 to a winding I25 of the relay 12 and by a-conductor I28to the conductor 84. A conductor I28 connects the winding I25 to theconductor 88. A housing I21 (Fig. 2) mounted on the top of the oven I8serves to enclose the relays 85 and 12 and the timer H8, and the lamp 88and the switch 82 are supported thereby in obvious and accessiblepositions.

In the operation of the apparatus described hereinabove, the dollies28-28 (Fig. 1) and the reels 28-28 are placed successively in the ovenI8 to fill the oven, which is heated by steam-supplied to the steampipes I1-I1, and the switch 82 (Fig. 8) is closed. After the apparatusis-in its normal operating cycle with the oven I8 filled with dolliesexcept for position A, which is vacant. and the timer II8 has been inoperation for a predetermined period of time, the main contact the relay85. 1

84 leads to a synchronous motor connected by a and the conductor 14.

. solenoid 46 causes the valve 4'4 to be actuated to 5 V I22 isclosed'by the timer. The closing of the main contact closes the circuitto the winding I26 01 the relay 12 and the winding is energized bycurrent from the power line 90 through the conductors 86 and I26 to thewinding I26, and through the conductors 9|, 93, 94 and I23, the maincontact 22, and the conductor I24.

When the winding I26 is energized, the winding 16 of the solenoid 45 is.supplied with current from the power line 90 through the conductors 9|,93, I1 and 16, and through the conductors 86 and 88, the contactor 62,the contact 60, the conductor 63, the contactor 64, the contact 66, theconductor 10, the contactor II, the contact 13, The energization of thesupply air under pressure to the left hand end of the cylinder 43, asviewed in Fig, 2, and to exhaust the right hand end thereof, whereby theram '42 draws the carriage 30 to its dotted line position, as shown inFig. 3. As the carriage 30 moves to the right the dogs 33--33 engage thedolly in position 13 and move that dolly to position A. The dollyadvanced by the carriage 30 pulls the entire train of dollies to theright through a distance dolly.

As the carriage 30 is movedto the-right, as viewed in Fig. 3, the arm 49is moved out of engagement with the spring-pressed arm 50, which movesto its dotted line position, thereby causing the engagement of thecontactor |02 (Fig 6) and the contact I03. When the dolly moved fromposition B to position A engages the arm 62 and moves it from its fullline position toits dotted line position, as shown in Fig. 1, theforward limit switch 51 is actuated and the contactor 62 is moved out ofengagement with the contact 60, whereby the circuit to the winding 15 ofthe solenoid 45 is broken, and the contactor 62 is moved into engagementwith the contact 6|.

As soon as the contactor 62 (Fig. 6) engages the contact 6|, the lamp 96is supplied with current through the conductors 9| and 93, and theconductors 86 and 88, the contactor 62, the contact 6|, and theconductors IN and M0, and the filament 95 of the lamp is lighted. Thelighting of the lamp 96 indicates that a dolly 23 and its reel 26 are inposition A, and can be removed from the oven l0.

Upon the engagement 6) and the contact 6|, lay 65 of the contactor 62(Fig. the winding 84 of the reis energized through the conductors 9|, 93and 94, and through the conductors 86 and 88, the contactor 62, thecontact 6|, the conductor l0|, the contactor I02, the contact I03, and

, the conductor I 04. The energization of the winding 84 moves thecontactors H0 and 83 into engagement with the contacts I06 and '82,respectively, and moves the contactor 64 out of engagement with thecontact 66.

When the engagement between the contactor 64 (Fig. 6) and the contact 66is broken, the circuits to the winding 15 of the solenoid 45, to theclutch coil H5, and to the motor H2 of the timer equal to the length ofone then causesthe valve 44 to be 6 the conductors 9|, 93 and I1, andthrough the conductors l6 and 81, the contactor 83, the contact 82, andthe conductor 8|. The solenoid 46 moved to the position in which itdirects air under pressure to the right hand end of the cylinder 43, asseen in Fig. 2, and exhausts air from the opposite end thereof, wherebythe carriage 30 is moved back along the trackway 32 to its full lineposition, as shown in Fig. 3. As the carriage is so moved, the dogs31-31 and 3333 rotate as they 'are moved past the abutment plates 26-26of thedolly in position B so that the carriage is not obstructed in itstravel. When the carriage reaches its full line position, the dogs 31-31engage the abutment 33 and are prevented from rotating in a clock-wisedirection. Also, when the carriage 30 reaches its full line position,the arm 49 strikes the spring-pressed arm 60 of the rear limit switch6|, which causes the engagement between the contactor I02 (Fig. 6) andthe contact, I03 to be broken, whereby the winding 84 of the relay 65 isde-energized.

When the winding 84 of the relay 61 (Fig, 6) is de-energized thecontactor 64 engages the contact 66 and the contractors H0 and 83 aredisengaged from the contacts I06 and 82, respectively, whereby thesolenoid 46 is de-energized. However, the valve 44 continues to supplyair under pressure to the right hand end of the cylinder 43 and thecarriage 30 is held in its full line position.

The circuit to the timer motor 2 (Fig. 6) is closed at this time exceptfor the contact 60 and the contactor 62, which are out of engagement.

Upon seeing the lighted lamp 96 (Fig. 2) an operator removes from theoven I0 the reel 26 and the dolly 23 which are in position A, and places3 are broken. The timer 3 then resets to;

zero, whereby the main contact I22 is opened which breaks the circuit tothe winding I25 of the relay l2 and the engagement :between thecontactor II and the contact 13 is broken.

' When the engagements are effected between the contactor 0 (Fig. 6) andthe contact I06, and the contactor 83 and the contact 62, the winding 60of the solenoid 46 is energized through another dolly and reel in theoven at the entrance end thereof, the dolly which is inserted beinghooked to the next adjacent dolly in the oven. Thus, the train. ofdollies is maintained throughout the length of the oven |0 except forposition A, which is vacant.

The removal of the dolly from position A permits the arm 52 to be swungto its full line position, as shown in Fig. 1,, by the spring-pressedarm 56, and the contactor 62 of the forward limit switch is moved intoengagementwith the contact 60. This causes the lamp 96 to be darkenedand completes the circuit to the motor 2 and the clutch coil H5 of thetimer 3. The timer motor I I2 is supplied with current from the powerline through the conductors 9|, 93 and 94, and through the conductors 86and 88, the contactor 62, which is in contact with the contact 60 whenno dolly is in position A, the contact 60, the conductor 63, and theconductor |20 which includes the limit switch |2I, which is closed. Theclutch coil H5, which is in parallel with the motor. I 2, also isenergized at this time.

Since the valve 44 (Figs. 1 and 2) at this time is in a position inwhich air under pressure is supplied to the right hand end of thecylinder 43, as viewed in Fig. 2, and the carriage 30 is held belowposition B, the dogs 3'|--31 then are held against the abutment 38 sothat the dollies 23-23 cannot be moved forward manually far enough toplace the end dolly in position A, which is the only position in whichit can be removed from the oven l0 through the exit opening IS. Thedollies cannot 'be moved to the rear because of the dogs 33-33.' Thus,none of the dollies in the oven may be moved manually along the tracks20 and 2| to position A.

The main contact i2 determined period of ime after the start oi! thetimer H3, which period is equal to the minimum period of time for dryingthe core portions on the reels 26-28 divided by the number of dollies23-23 which may be contained in the oven ill. The timer '1 l3, ofcourse, may be adjusted suitably.

While the main contact I22 (Fig. 6) is open the circuit to the windingI25 of the relay 1! is open and the contactor H and the contact 13 areout of engagement, whereby the circuit to the winding 15 of the solenoid45 is open. H3 has operated for the predetermined period of time, itcloses the main contact I22 and the cycle of operation describedhereinabove is repeated.

The dogs 31-31 (Fig. 3) are held by the abutobstructing the movement ofthe dollies 23-23 when the carriage is in its rear position.Consequently, the dollies cannot be moved manually to position A andeach remains in the oven Ill for the required minimum period of time ofdrying.

The apparatus described hereinabove is entirely automatic and anoperator thereof need only insert the loaded dollies into and removethem from the oven l0. Consequently, while very little efiort andattention are required, each reel will be dried for the required minimumof time. I

What is claimed is:

1. In a drying apparatus including an elongated enclosure having anentrance and an exit, reciprocable means movable from a startingposition to a forward position for moving a series of articles arrangedin tandem through the enclosure; means for driving the moving means andmeans for preventing movement of articles moved by the moving meansexcept by the moving means, means for controlling the operation of thedriving means which comprises a starting solenoid for causing thedriving means to drive the reciprocable means from its starting positionto its forward position to move a series of articles toward the exit endof the enclosure, a reversing solenoid for causing the driving means todrive the reciprocable means from its forward position to its startingposition, and a limit switch positioned near the exit of the enclosureand servin when engaged by an article moved by the reciprocable means tothe exit-to tie-energize the starting solenoid and to energize thereversing solenoid.

2. In a drying apparatus including an elongated enclosure having anentrance and an exit, reciprocable means movable from a startingposition to a forward position for moving through the enclosure a seriesof articles arranged in tandem and means for driving the moving means.means for controlling the movement of articles positioned in theenclosure which comprises means for preventing movement of the articlesexcept by the moving means, a startingsolenoid for causing the drivingmeans to drive the reciprocable means from its starting position to itsforward position to move a series of articles toward the exit end oftheenclosure when energized, a reversing solenoid for causing the drivingmeans to drive the reciprocable means from its forward position toitsstarting position when energized, a switch serving when actuated todeenergize the starting solenoid and to energize the reversing solenoid,means positioned near the exit of the enclosure for actuating the switchwhen engaged by an article moved by the reperiod (Fig. 6) is open for aprefor reciprocating gaging the actuating means is removed fromciprocable means to the exit, means for de-energizing the reversingsolenoid when the reciprocable means is moved to its starting P sition,a second switch for causing the energization of the starting solenoid,and a timer in circuit with the first switch and started when thearticle enthe exit of the enclosure for closing the second switch at theend of a predeterminedperiod of time after the article is removed.

3. In a drying apparatus including an elongated enclosure having anentrance and an exit, reciprocable means movable from a startingposition to a iorward position for moving a -'series of articlesarranged in tandem through the enclosure, means for driving the movingmeans and means for preventing movement of articles in the enclosureexcept by the moving means, means for controlling the operation of thedriving means which comprises a starting solenoid for causing thedriving means to drive the reciprocable means from its starting positionto its forward position to move a series of articles toward the exit ofthe enclosure when energized, a reversing solenoid for causing thedriving means to drive the reciprocable means from-its-forward positionto its starting position when energized, a double throw limit switchpositioned near the exit of the enclosure serving when engaged by anarticle moved by the reciprocable mearisto the exit to de-energize thestarting solenoid and energize the reversing solenoid, means forde-energizing the reversing solenoid ,when the reciprocable means ismoved to its starting position, a starting switch in series with thestarting solenoid for causing its energization, and a timer started whenthe article moved to the exit of the enclosure is removed therefrom forclosing the starting switch a predetermined period of time after thearticle at the exit is removed. 4

4. In a drying apparatus including an enclosure having an entrance andan exit, a track extending from the entrance to the exit of theenclosure,

a series of connected article-carrying dollies movable along the track,a carriage having ratchet means thereon for engaging one of the dollieswhen moved toward the exit of the enclosure to move the dolliestherewith and pneumatic means the carriage along the track a distanceequal to the length of one of the dollies, means for controlling themovement of the dollies which comprises means for preventing move-' mentof the dollies when the carriage is not reciprocated, a valve forcontrolling the pneumatic means, the valve so as to cause the pneumaticmeans to move the carriage toward the exit of the enclosure whenenergized, a starting switch for causing the energization of thestarting solenoid when closed, a reversing solenoid foractuating thevalve to cause the pneumatic means to move the carriage away from theexit of the enclosure 'when energized, a timer for closing the startingswitch after it has-run a predetermined period of time, a reversingswitch serving to stop the timer, de-energize the starting solenoid andenergize the reversing solenoid when actuated and start the timer whenunactuated, and means ositioned in the path of the dollies at a pointadjacent to the exit of the enclosure for actuating the reversing switchwhen struck by one of the dollies moved to the having a startingsolenoid for actuating move the dollies therewith and pneumatic meansfor reciprocating the carriage along the track a distance equal to thelength of one of the dollies, means for controlling. the movement of thedollies which comprises means for preventing movement of the dollieswhen the carriage is not reciprocated, a valve for controlling thepneumatic means, starting solenoid to cause the pneumatic means to movethe car riage toward the exit of the enclosure when energized, astarting switch for causin the energization of the starting solenoidwhen closed, a reversing solenoid for actuating the valve to cause thepneumatic means to move the carriage away enclosure when energized,atimer for closing the starting switch after it has run a predeterminedperiod of time, a doublethrow switch serving to stop the timer,de-energize the starting solenoid and energize the reversto the exit,said double-throw switch serving to restart the timer when the dollymoved to the exit is moved out of engagement therewith.

6. In a drying apparatus including an elongated enclosure having anentrance and an exit, a train of connected dollies positioned in theenclosure and movable therealong, a reciprocable ratchet mechanism formoving the train of connected dollies toward the entrance or theenclosure a. distance equal to the length of one of the dollies at eachreciprocation thereof and pneumatic means for reciprocating the ratchetmechanism, means for controlling the movement of the train of dollieswhich comprises means for preventing movement of the train of dolliesrelative to the enclosure when the train of dollies is not moved by theratchet mechanism, a supply line associated with the pneumatic means, a.valve positioned in the supply line serving to cause the pneumatic meansto move the ratchet mechanism toward the exit of the an advancingposition and cause the pneumatic means to move the ratchet from the exitwhen in a reversing position, starting electromagnetic means for movingthe valve to the advancing position, reversing electromagnetic means formoving the valve to its reversing position, a timer in circuit with thestarting electromagnetic means for energizing that electromagnetic meansafter it has run a predetermined period of time, and a limit switchpositioned so as to be engaged dollies which is moved to the exit of theenclosure and serving to stop and reset the timer, de-energize thestarting solenoid and energize the reversing solenoid when so engaged.

7. In a drying apparatus including an elongated enclosure having anentrance a train of connected dollies positioned in the en-'- closureand movable therealong. a reciprocable ratchet mechanism for moving thetrain of connected dollies toward the entrance of the enclosure adistance equal to the length of one of the mechanism away and an exit,

' matic means for reciprocating the ratchet mech anism, means forcontrolling movement of the train of dollies which comprises means forpreventing movement of the train of dollies relative to the. enclosurewhen the train of dollies is not moved by the ratchet mechanism, asupply line, a

four-way valve connecting the supply line to the I pneumatic means, astarting solenoid ior actuat for actuating the valve enclosure when inby the one ofthe 6o dollies at each reciprocation thereof and pneuingthe valve to cause the pneumatic means to drive the ratchet mechanismtoward the exit of the enclosure when energized, a reversing solenoidfor actuating the valve to cause the pneumatic means to drive theratchet mechanism away from the exit when energized, a starting relayincluding a winding and normally open contacts in series with thestarting solenoid for energizing that solenoid when energized, anautomatically resetting timer having, a motor and normally open timercontacts in series with the winding of the relay and serving to closethe timer contacts a predetermined period of time after the timer isstarted, whereby the starting solenoid is energized a predeterminedperiod of time-after the timer is started, a reversing relay having awinding and normally open contacts in series with the reversing solenoidfor energizing the reversing solenoid when throw limit switch positionedin the path of the dollies at the exit of the enclosure and having astarting contact in series with the motor of the timer, a. reversingcontact in series with the reversing relay-and a contactor normally inengagement with the starting contact thereof but movable out ofengagement therewith and into engagement with the reversing contactthereof when the limit switch is engaged by one of the dollies moved tothe exit 01 the enclosure, whereby the timer resets, the startingsolenoid is deenergized and the reversing solenoid is energized when oneof the dollies is moved to the exit, and a stopping limit switch havingnormally closed contacts in series with the winding of the reversingrelay and positioned so that the contacts thereof are opened by theratchet mechanism at the end of a reciprocation thereof, whereby thereversing relay is de-energized and the reversing solenoid isde-energized at the end of a reciprocation of the ratchet mechanism.

FRED D. JOHNSTON. VERNON C. ENSOR.

file of this patent:

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